2011 Shoot Growth

Seasonal Overview

Despite forecasts of a warmer growing season, this spring has been well below average and in most areas we are trending even behind last year.  Several storms in May brought rain and cold temperatures throughout the state.  Another storm will likely hit coastal areas this coming weekend with temperatures expected to warm up to mid 70s and low 80s late next week.  As bloom becomes more prevalent, we may see effects of rain and cold temperatures on berry set.  Bloom is at various stages throughout the state and the effects of rain, hail, and generally cold temperatures will be addressed in the next posting.

Emerging from the La Nina climate of 2010, the Pacific Ocean has been warming up.  These warmer waters bring warmer air temperatures in the Spring when onshore winds are common.  However, the exception to this current trend is the West Coast of North America where water temperatures are remaining quite cold.  As ocean temperatures continue to warm up, we should expect to see air temperatures follow suit.

The tables below illustrate growing degree days and precipitation data.  The current season is compared to historical averages and last year to give a relative idea of how we are tracking.

Grape Growing Degree-Days
March 15 – May 18
  This Year Last Year Normal* Actual Days Compared to Normal** Actual Days Compared to Last Year**
Mendocino County          
Ukiah NCDC (9122) 330 377 493 -26 -8
Hopland CIMIS (85) 299 323 405 -20 -4
Lake County          
Kelseyville 314 313 433 -25 0
Red Hills 356 336 433 -7 2
North Valley          
Manteca CIMIS (70) 503 525 613 -14 -3
Lodi CIMIS (166) 492 538 659 -19 -5
Napa / Sonoma          
Oakville CIMIS (77) 472 454 569 -13 2
Santa Rosa CIMIS (83) 302 305 504 -38 -1
Carneros CIMIS (109) 409 427 564 -22 -3
San Luis Obispo          
SLO CIMIS (52) 466 466 564 -25 0
Monterey County          
King City CIMIS (113) 422 473 593 -25 -7
San Benito          
Hollister CIMIS (126) 417 422 501 -16 -1

* “Normal” degree-days are calculated by taking the average of at least 5 years of historical data.

** Comparative columns illustrate actual days ahead (+) or behind (-) the current season is tracking with historical average and last year.  For example, a +1 in “Compared to Normal” illustrates the growing season is one day ahead of historical average.

Spring Rain (inches)
March, April, May
  2011 2010 Historical Average
Mendocino County      
Hopland CIMIS (85) 14.0 12.0 9.4
North Valley      
Lodi CIMIS (166) 5.0 4.2 3.5
Napa / Sonoma      
Oakville CIMIS (77) 16.2 10.6 8.4
Santa Rosa CIMIS (83) 14.0 10.2 7.8
Monterey County      
King City CIMIS (113) 4.7 3.7 2.8
San Benito      
Hollister CIMIS (126) 3.3 5.8 3.4
San Luis Obispo      
SLO CIMIS (52) 8.0 4.7 4.8

Napa, Sonoma

Andrew Nelson

Warm temperatures in early May helped facilitate growth but this was stopped short by colder temperatures, rain, and even hail in some areas.  Based on degree day models, we are currently trending almost exactly with last year. Compared to average, Napa is 10 to 14 days behind and Sonoma is closer to 3 weeks.

Current vine growth has been slow.  Average shoot length in more vigorous varieties (Cabernet and Sauvignon Blanc) is between 1-3 feet on valley floor, with 1-2 feet in hillside blocks.  Chardonnay and Pinot Noir are slightly less at 1.5 to 2.5 feet.  Napa blocks of Merlot seem to have even less growth with 1-2 feet on average.

Managing vine vigor has been a major topic for 2011.  In 2010 creating a balanced vine proved to be difficult in the wet and mild temperatures.  Our strategy last year included aggressive leafing in specific blocks to open the canopy and create more fruit exposure and airflow.  This ended up resulting in additional sunburn when temperatures spiked in late August and scorched clusters not accustomed to high temperatures.  This year we have modified farm plans to create a more balanced and open canopy using alternative methods to aggressive leafing.  Pictured below are two sites known for high vigor (Rutherford Cabernet and Sauvignon Blanc) that illustrate different methods we are using to create balance in a season that is abnormally cool and wet.

Disposable “kicker canes” at this Cabernet site in Rutherford are tied to the drip wire for easy removal after berry set. This “disposable” growth acts as an alternative energy sink for the vine rather than producing additional shoots and congestion in the fruit zone. By taking this energy away from the vine, we should have a more balanced canopy that requires less manipulation and promotes improved fruit maturation.

This block of Rutherford Sauvignon Blanc is more vigorous in the southern portion (right of the yellow tie). Here we have not disked the cover crop which will pull additional moisture from the soil rather than leave the water available to the vines. In the northern portion (left) we have disked every row. Also, we delayed suckering in the southern portion to act as an additional energy sink.

Mendocino & Lake, Northern Sonoma & Northern Napa

Terese Geniella

Spring in fits and starts is the story of May 2011 on the North Coast.

It has been wet and cool with a few days of 70 to 80 degrees.  The expectation of a warm June has been liquidated by current weather patterns of showers into the first week of June.  As of May 31st, the grape growing year is about 10 days behind normal in Napa up valley (St Helena and Calistoga) and southern Mendocino County, and 20 days behind in Potter Valley and Lake County.

Vines are growing beautifully with the moisture and the intermittent warm sunny days.  Bloom has started and is getting rained on, and is behind 10 to 14 days of average dates.  Cabernet Sauvignon shoots are above the top wire, with tendrils, compared to more northern Cabernet in Mendocino and Lake Counties at 20 to 30 inches.

Chardonnay shoot growth is showing the pattern of the cool season with shoots 3 to 4 feet in the more temperate regions of Santa Rosa and Healdsburg, compared to Chardonnay in Potter Valley at 20 inches.

Sauvignon Blanc growth in Calistoga is ahead of the northern counties, as Sauvignon Blanc and Pinot Noir in Potter Valley are barely 15 inches on some blocks.  A Calistoga grower says it’s more like Russian River Valley weather than northern Napa Valley.

In general, expected grape crop size is average to minus average.  Counts post bloom and set will give more realistic numbers.  The cool rainy weather pattern this week may affect bloom and set and decrease estimates.

According to their cluster counts, growers are talking about a light chardonnay crop, but it’s varied by vineyard.  Chardonnay clusters may size up, making up for the lower cluster numbers, resulting in more chardonnay tons than predicted, as occurred with the 2009  ‘bumper’ crop of chardonnay.

Sauvignon Blanc in Potter Valley.

Lodi, Solano, Yolo and Contra Costa

Ron Pieretti

Lodi is still definitely behind with just a few growers having completed suckering and shoot selection. Most growers are waiting to the last minute to complete this pass and some are not going to do it at all. There are concerns about a possible short harvest with a lot of single and sterile shoots present. Nobody can give an accurate insight on the size of the crops but the feeling is it could be short up to 10% or more. We have seen some bloom in Chardonnay and there is concern about set with storms still eminent.  We are possibly up to 14 days behind in some areas but once the weather shifts we may catch up quickly. This past week some growers reported an inch of rain during the last storm making fields hard to enter.

Sac /Delta is fairly similar, however, during this past storm there were reports of hail and some canopy damage, especially around Clarksburg. We have about 10% bloom in some blocks and it is unclear if the hail will have an effect on set.  Up to 10 days behind.   An Interesting note, 5/17 was the lowest daily high on record.

Contra Costa shows signs of the most even shoot growth with most vineyards completing shoot selection this week. Again reports of up to an inch of rain from the past storm with some vineyards  just showing signs of bloom. Growers report they seem behind by 7-10 days.

Yolo / Solano are also slightly behind by about 7-10 days with an average of 12 to 16 inches out.

Monterey, Paso Robles

Matt Wilson

The Central Coast has seen unseasonably cool and wet weather this past week.  The forecast for the next 2-3 weeks is for average to below average temperatures throughout Monterey County and Paso Robles areas. This translates to highs around 70 for Monterey County and 80 for Paso Robles.  There is also a possibility of more rain for Monterey County at the end of next week.

Shoot growth trends are sporadic throughout the Central Coast.  We had frost damage throughout the region back in mid-April, and since then vines have bounced back, but still seem to be 2-3 weeks behind.  I have seen some vineyards that were unaffected by frost or shoot thinned early that have excellent growth 18”-24”, while others that were even slower to come out after the frost event are still only at about 6”-12”.  There is a lot of available water and the vines seem to want to take off, but the soils are still cool and growth is progressing slowly.

The Chardonnay crop appears to be quite light, based on cluster counts throughout the Central Coast.  The Red grape counts, in general, appear to be average to below average depending on the variety and the vineyard. At this stage, there does not appear to be a bumper crop in any varietals this season.

San Luis Obispo, Santa Barbara

Stasi Seay

This area was most affected by recent storms with 1.39” during the week of May 15. The extended wet weather, combined with mild temperatures, have created a high mildew pressure occurrence. Shoot growth has finally begun with Pinot Noir at 18”-24” lengths. The Chardonnay is a bit behind at 12”-18”. Weak shoot thinning began last week in the Pinot Noir. There are significant numbers of sterile shoots in Chardonnay and Pinot Noir cluster counts are at an average count. Bloom has begun in the Edna Valley in the higher elevations.

In Santa Barbara County, recent storms were light in precipitation but cold. This has caused growth to be behind seasonal averages by about a week. Shoot growth in Chardonnay is at 12”-18”. As in other Central Coast areas, sterile shoots are common and the cluster counts are down. Shoot thinning will begin soon, although growers are cautious, given the low crop count. Canopy management will be the topic of focus for this season as vine balance will be important for quality.


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